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Scientists have found more than 50 tiny fragments of a meteor that exploded over Russia's Ural Mountains with the power of dozens of atomic bombs. Most are less than a centimeter in diameter, but locals saw a big meteorite fall into the lake on Friday, leaving a 6-m-wide hole in the ice. A meteor up to 50-60 cm could eventually be found in the lake.

After sifting through four years of data from NASA’s Fermi Gamma-ray Space Telescope, a research team has found the first unambiguous evidence of how cosmic rays are born. The new study confirms what scientists have long suspected: Cosmic rays—energetic particles that pelt Earth from all directions—are born in the violent aftermath of supernovas, exploding stars throughout the galaxy.

A meteor that scientists estimate weighed 10 tons (11 tons) streaked at supersonic speed over Russia's Ural Mountains on Friday, setting off blasts that injured nearly 1,000 people and frightened countless more. The Russian Academy of Sciences said in a statement that the meteor over the Chelyabinsk region entered the Earth's atmosphere at a speed of at least 54,000 kph (33,000 mph) and shattered about 30-50 km (18-32 miles) above ground.

According to Jay Melosh, a distinguished professor of earth, atmospheric and planetary sciences and physics and aerospace engineering at Purdue University, if the asteroid rapidly approaching us this week were to impact rather than nearly miss Earth, it would explode with a four-megaton force near what the military calls optimum height for damage. This asteroid would release only half the energy of the Siberian strike in 1917, but the 30,000-foot detonation height could cause significant property damage and loss of life.

Researchers searching the galaxy for planets that could pass the litmus test of sustaining water-based life must find whether those planets fall in what’s known as a habitable zone. New work, led by a team of Penn State University researchers, will help scientists in that search.

Ridges in impact craters on Mars appear to be fossils of cracks in the Martian surface, formed by minerals deposited by flowing water. Water flowing beneath the surface suggests life may once have been possible on Mars.

The universe abounds with dark matter. Nobody knows what it consists of. Now, University of Oslo physicists have launched a very hard mathematical explanation that could solve the mystery once and for all.

University of Leicester planetary scientists have found new evidence suggesting auroras—similar to Earth's Aurora Borealis—occur on bodies outside our solar system. Auroras occur on several planets within our solar system, and the brightest—on Jupiter—are 100 times brighter than those on Earth. However, no auroras have yet been observed beyond Neptune.

In 2004 the Supernova Cosmology Project used the Hubble Space Telescope to find a tantalizing supernova that appeared to be almost 10 billion light-years distant. But Lawrence Berkeley National Laboratory scientists had to wait until a new camera was installed on the Hubble years later before they could confirm the candidate's identity and redshift as a Type Ia "standard candle." The spectrum and light curve of supernova SCP-0401 are now known with clarity; it is the supernova furthest back in time that can be used for precise measurements of the expansion history of the universe.

Where do we come from? What is the universe made of? Will the universe exist only for a finite time or will it last forever? These are just some of the questions that University of California, San Diego physicists are working to answer in the high desert of northern Chile.

Images taken by the framing camera onboard NASA's space probe Dawn show two enormous craters in the southern hemisphere of the asteroid Vesta, a remarkable protoplanet that is a time capsule of early planet formation in the solar system. Scientists have recently found that the asteroids that created these impact features also delivered dark, carbonaceous material to the protoplanet.

The quest for a twin Earth is heating up. Using NASA's Kepler spacecraft, astronomers are beginning to find Earth-sized planets orbiting distant stars. A new analysis of Kepler data shows that about 17% of stars have an Earth-sized planet in an orbit closer than Mercury.

Researchers from Canada, California, and Poland have devised a straightforward way to test an intriguing idea about the nature of dark energy and dark matter. A global array of atomic magnetometers—small laboratory devices that can sense minute changes in magnetic fields—could signal when Earth passes through fractures in space known as domain walls. These structures could be the answer to the universe’s darkest mysteries.

Researchers from the U.S. and Canada have proposed a method for cooling trapped antihydrogen which they believe could provide "a major experimental advantage" and help to map the mysterious properties of antimatter that have to date remained elusive.

A collaboration has made a precise measurement of elusive, nearly massless particles, and obtained a crucial hint as to why the universe is dominated by matter, not by its close relative, antimatter. The particles, called antineutrinos, were detected at the underground Daya Bay experiment, located near a nuclear reactor in China, 55 km north of Hong Kong.

Just in time for the holidays, NASA's Cassini spacecraft, in orbit around Saturn for more than eight years now, has delivered another glorious, backlit view of the planet Saturn and its rings.On Oct. 17, 2012, during its 174th orbit around the gas giant, Cassini was deliberately positioned within Saturn's shadow, a perfect location from which to look in the direction of the sun and take a backlit view of the rings and the dark side of the planet.

An international team of scientists has discovered that Tau Ceti, one of the closest and most Sun-like stars, may have five planets. The surprise finding was the result of combining more than 6,000 observations from three different instruments and applying intensive modeling to the data. New techniques allowed the scientists to find signals half the size previously thought possible.

Black holes, stellar coronae, and supernovae are all composed of hot plasma at several million degrees Celsius. The gases in these objects are powerful emitters of X-ray, but theoretical astrophysical have not yet been able to explain the observed intensities of these X-rays for the most prominent species, iron ions. A team has now successfully used an X-ray laser to perform spectroscopy on highly ionized iron ions, obtaining new insights not granted by previous methods and potentially leading to a solution to this 40-year-old puzzle.

In much the same way that a plane is jolted back and forth by invisible gusts of wind, turbulence is common in space, where chaotic motions affect the movements of ionized gas, or plasma. A research team led by the University of Iowa reports to have directly measured this turbulence for the first time in the laboratory.

While some theoretical physicists make predictions about astrophysics and the behavior of stars and galaxies, others work in the realm of the very small, which includes quantum physics. Such is the case at the University of California, Santa Barbara, where theoretical physicists at the Kavli Institute for Theoretical Physics cover the range of questions in physics. Recently, they have made important strides in studying a concept in quantum physics called quantum entanglement, in which electron spins are entangled with each other.

Black holes are surrounded by many mysteries, but now researchers from the Niels Bohr Institute, among others, have come up with new groundbreaking theories that can explain several of their properties. The research shows that black holes have properties that resemble the dynamics of both solids and liquids.

A decade ago, a British philosopher put forth the notion that the universe we live in might in fact be a computer simulation run by our descendants. While that seems far-fetched, perhaps even incomprehensible, a team of physicists at the University of Washington has come up with a potential test to see if the idea holds water.

A North Carolina State University researcher has taken a "snapshot" of the way particles combine to form carbon-12, the element that makes all life on Earth possible. And the picture looks like a bent arm.

A team of astronomers led by the University of Leicester in the U.K.has uncovered new evidence that suggests that X-ray detectors in space could be the first to witness new supernovae that signal the death of massive stars. The possibility stems from the finding that gamma-ray bursts from the largest supernovae are accompanied unique thermal X-ray signatures that can be observed by detectors now in place.

As far back in time as astronomers have been able to see, the universe has had some trace of heavy elements, such as carbon and oxygen. These elements, originally churned from the explosion of massive stars, formed the building blocks for planetary bodies, and eventually for life on Earth. Now, researchers have peered far back in time, to the era of the first stars and galaxies, and found matter with no discernible trace of heavy elements.